The United States is ready to widen arms supplies to Ukraine to help build up the country's naval and air defense forces in the face of continuing Russian support for eastern separatists, the U.S. special envoy for Ukraine told The Guardian.

Kurt Volker told the newspaper in an interview published on September 1 that pro-Western, anti-Russian sentiment was growing in Ukraine and that the Trump administration was "absolutely" prepared to go further in supplying weaponry to Ukrainian forces than the antitank missiles it delivered in April.

"They are losing soldiers every week defending their own country," Volker, a former U.S. ambassador to NATO, said in the interview.

"And so in that context it’s natural for Ukraine to build up its military, engage in self-defense, and it's natural to seek assistance and is natural that other countries should help them. And of course they need lethal assistance because they’re being shot at," he added.

Moscow's takeover of Ukraine's Crimean Peninsula and its support for separatists in eastern Ukraine prompted the United States, the European Union, and others to impose sanctions on Russia.

Russia seized Crimea in March 2014 after sending in troops, taking over key facilities, and staging a referendum deemed illegitimate by at least 100 countries in the United Nations.

The Kremlin, which has denied sending troops and heavy weapons to the region, has said providing new lethal weapons to Ukraine would foment bloodshed.

Volker said that, while time was not on Russian President Vladimir Putin's side, he would nonetheless likely wait for presidential and parliamentary elections in Ukraine next year before reconsidering his negotiating position.

"We can have a conversation with Ukraine like we would with any other country about what do they need," Volker said, according to the Guardian.

"I think that there’s going to be some discussion about naval capability because as you know their navy was basically taken by Russia. And so they need to rebuild a navy and they have very limited air capability as well. I think we’ll have to look at air defense," he added.